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Sunday, January 8, 2017

Snow Day

Atlanta had one of its snowless Snow Days on Friday in which schools, workplaces, and virtually the entire city closed down in order to allow everyone to rush to the grocery for bread, milk and batteries ahead of the impending Snowmageddon! (And, skeptics, we did get a little ice Friday night, so it was totally and completely justified.) So after everyone fled the Garden, I took the opportunity to take some leisurely pictures in the Orchid Display House. It was quiet and lovely in the semi-twilight.
See what you missed? Don't worry, most of these guys will still be in flower next week, plus many more. And don't forget, the Fuqua Orchid Center is one of the best places in town to spend a cold January day.

Wednesday, January 4, 2017

Bulbophyllum arfakianum

Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum ABG 20050050
Bulbophyllum arfakianum unfurled its flowers for the first time last week, and I was felled on the instant. There isn't a single vantage point from which the flower doesn't look ravishing. Bulbophyllum arfakianum is native to West Papua, Indonesia. The specific epithet, arfakianum, references the Arfak Mountains, an outstandingly rich region of biological diversity on the Bird's Head Peninsula. Bulbophyllum arfakianum grows as an epiphyte in lowland forest at 50 to 400 meters elevation.

Bulbophyllum arfakianum ABG 20050050
How many other flowers can you think of that look as fantastic from the back as the front?

Sunday, January 1, 2017

New Year's Day 2017

Acineta erythroxantha ABG 20050050
Happy New Year, everyone!! I want to wish you all a joyful new year. May 2017 be filled with discovery and delight in all of the botanical magnificence around us.


Thursday, November 3, 2016

The Other Slipper

Our magnificent Phragmipedium caudatum would have attracted far more admirers were it not for the raspberry kovachii flowering simultaneously on the waterfall. The lucky visitors who managed to tear themselves away and explore the back of the High Elevation House found this beauty overlooking the Sun Pitchers (Heliamphora) and bromeliads.

The markings on the oversized drooping sepals of Phragmipedium caudatum remind me of fenestrations, the translucent 'windows' characteristic of the pitchers of Nepenthes aristolochiodes, Sarracenia psittacina, and the flowers of Bulbophyllum grandiflorum. Fenestrations are thin parts of the leaf or flower that allow light to be seen by an insect trapped in the interior, but aren't actual exits. In carnivorous plants, the insect flies into the 'windows' in the leaves over and over until it tires and slides into the liquid below. Fenestrations in a flower direct the pollinator toward the anther and stigma, but I don't know if the markings on Phragmipedium caudatum function in this way.

Phragmipedium caudatum grows on rocky seepage slopes at 1,500 to 2,000 meters elevation from southern Mexico to Peru. Our plant is embedded in live sphagnum on a large granite rock in the High Elevation House where it receives a 75º daytime maximum temperature and a 52º nighttime minimum. This week, it has three flowers open simultaneously.

Friday, October 21, 2016

Phragmipedium kovachii

Phragmipedium kovachii, the most notorious orchid discovery within recent memory, is flowering now in the Tropical High Elevation House.

It's growing high on the waterfall, perched on mossy rocks among two other slipper orchids, Phragmipedium besseae and Phragmipedium schlimii. This is the first flowering for our plant, which is a laboratory produced seedling purchased from Piping Rock Orchids in 2009.

In the wild, Phragmipedium kovachii grows in cloud forests at 2,000 meters elevation near Moyobamba, Peru on limestone seepage sites. Since it first caught the attention of growers and scientists outside of Peru, P. kovachii has practically become a poster child for bad behavior within the horticultural/botanical community -the illegal poaching of a protected orchid by a private collector, followed by an astonishing display of poor judgement by the botanists who took possession of it. You can find a detailed account of the story in Craig Pittman's The Scent of Scandal (2012 University of Florida Press). Pittman is a reporter for the Tampa Bay Times who has covered the kovachii story since 2003. It's a fascinating story and it underscores the importance of following the law when self interest, science and the law conflict. I think of the kovachii story as a cautionary tale and I believe Pittman's account should be required reading for anyone who works with orchids at a botanical garden.

Friday, September 9, 2016

Bullish on Stanhopeas

Stanhopea hernandezii
For a long time I thought of Stanhopea hernandezii as a sort of junior sized version of Stanhopea tigrina, that mastodon of the stanhopeas. Both give the impression of a massive cranium and formidable tusks. But it wasn't until this summer when we flowered both species simultaneously that I was able to compare them side by side.
Stanhopea tigrina
In profile, it's easy to see that the the bottom of the hypochile is rounded like a bowl in hernandezii, but flattened in tigrina.
Stanhopea tigrina, a second color form
Stanhopea hernandezii, dorsal view
The horns are round in cross section and slender in hernandezii, but flattened and broad near the base in tigrina.
Stanhopea tigrina, dorsal view
Stanhopea tigrina, dorsal view
Stanhopea hernandezii, lip and column
Notice the striking difference in the columns of the two species: hernandezii's narrow column compared with tigrina's broadly winged column.
Stanhopea tigrina, lip and column
Stanhopea tigrina, lip and column
Stanhopea hernandezii, lip
With the column removed you can see how much broader the epichile is in tigrina than in hernandezii.
Stanhopea tigrina, lip
Stanhopea tigrina, lip
Stanhopea hernandezii, lip in ventral view
Stanhopea tigrina, lip in ventral view
Stanhopea tigrina, lip in ventral view
Stanhopea hernandezii, column
Stanhopea tigrina, column
Stanhopea tigrina, column
Stanhopea hernandezii and tigrina are both endemic to Mexico. S. hernandezii occurs on the southwestern slopes of the Mexican plateau at about 1,600 to 2,000 meters elevation in the states of Morelos, Mexico and Michoacan. I can't find referennce to a specific pollinator for hernandezii. The largest fragrance components measured by Gerlach (in Lankesteriana 2010) are cinnamyl acetate (64%) and benzyl acetate (11%).

Stanhopea tigrina is known from  the eastern slopes of the plateau at about 1200 to 1800 meters in the states of Tamaulipas, Hidalgo, Puebla and Vera Cruz. Its pollinator is Euglossa viridissima. The chocolate fragrance described so often in the literature (but which I cannot discern in our plants) derives from the combination of phenylethyl-acetate, a primary component of the fragrance, and vanilline, one of the secondary components, according to Rudolf Jenny.

Our S. hernandezii, which we received from a commercial nursery as S. ecornuta, flowered in August and probably won't be on display again until next summer. On the other hand, we have quite a few S. tigrina in our collection. The flowers only last about three days, but it's definitely worth stopping by to try to catch them when they flower in August and September. They are magnificent.

Tuesday, August 9, 2016

Our War On Slugs

These days, 7 am finds me iphone flashlight in hand, visiting each greenhouse, searching the orchid collection for slugs, who I then crush under foot. This summer has brought an unusual amount of slug activity in all of our greenhouses, an unexpected development in the middle of a bright dry summer. They have made their way into pots and hanging baskets, eating root tips, new shoots, young flower spikes and flowers.

One triumph in our war on slugs has been among the Bucket Orchids (Coryanthes), usually a prime favorite of slugs, bush snails, cockroaches and practically any other pest you can name. Everybody, it seems, loves a Coryanthes. But this year the Coryanthes are producing flush after flush of absolutely pristine new roots and shoots. Our secret weapon: diatomaceous earth applied to bare root plants.

Diatoms are unicellular algae with lots of silica in their cell walls. Silica is the major constituent of sand, but it is also found in living organisms. The fossilized remains of diatoms are mined from deposits in the western US, Canada and Germany. The granulated product has industrial uses in filtration systems. Diatoms can also be milled to create a talcum-like powder, called diatomaceous earth, which is abrasive, porous and hygroscopic (moisture absorbing). Diatomaceous earth kills insects and mollusks by abrasion and dehydration.

We began our campaign against slugs on our Coryanthes two years ago. The battle plan had two phases: Remove their sanctuary and then apply treatment. First, we removed all of our Coryanthes from their pots and washed away the mossy medium and the slug eggs; then we mounted the plants on wooden rafts or tree fern slabs so that their roots were exposed and there were fewer places for mollusks to hide.

We began applying diatomaceous earth to our Coryanthes at the height of the slug and bush snail season. Bush snails are tiny. Dozens can hide in the crevices between pseudobulbs. A good way to monitor slug and snail populations is to check the exterior of the raft an hour after watering. Before treatment, I found at least one slug and 10 to 50 bush snails on each wooden raft. We applied diatomaceous earth weekly throughout the spring and summer to the exposed roots, in between the pseudobulbs and to the leaves.

This summer, after renewed applications, there are 0 to 2 bush snails per plant and no sign of chewing damage to root tips or leaves from slugs or cockroaches. We plant to continue applications through the autumn.

A few tips for using diatomaceous earth for slug, snail and cockroach control:

  • Look for "Food Grade Diatomaceous Earth" in order to get freshwater diatoms. Avoid "Pool Grade," which is saltwater-derived.
  • Keep the package sealed and out of the greenhouse or any other humid environment. The powder is highly porous and once it absorbs water from the atmosphere, it loses its ability to dehydrate pests.
  • Wear a dust mask. Silica dust is harmful to lung tissue.
  • Apply diatomaceous earth once a week to the entire plant and its mount when the surfaces are dry: the new shoots, leaves, flower spikes, the slab and in between pseudobulbs. Let it sit at least overnight before you water again, since water will wash it away.
  • Any soft brush will work as an applicator, but I like the idea of battling an enemy with a cosmetic brush. Drugstores carry them.

Sunday, July 31, 2016

Catasetum expansum x 3

In the stranger-than-fiction world of Catasetum flowers -where male and female flowers look so different that they were once classified as different species, and male flowers fire their pollen like missiles -it is the male flowers that are the peacocks and warrior princes with bold colors, sometimes elaborately fringed, toothed or spotted. Male Catasetum expansum flowers have an especially large shield shaped lip. In the center of the lip is a cavity, like a truncated spur, with thick fleshy walls. The cavity doesn't secrete nectar like a spur, but is a source of fragrance for fragrance-collecting Euglossine bees.

This week in our back up greenhouses, we have three different color forms of male Catasetum expansum flowers. First in this regiment is a handsome olive color form with a blood red center and plenty of red war paint. Release of the pollen masses is triggered by a touch to the downward pointing bristle in the center. In the photo above, notice that the flower in the upper left corner still has its pollen payload, while the flower in the center has already fired its two pollen masses.

Our second color form has pale green petals and sepals against a rich yellow-gold lip.

The most common form in our collection is a soft mint nonpareil color, to my eye the most soothing of the three. Catasetum expansum has a surprising range of color forms for a species with a relatively small distribution -northeastern Ecuador, where it grows as an epiphyte in seasonally dry forests from sea level to 1500 meters elevation.

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